Work vehicles, such as tractors, combines, front-end loaders, excavators, and the like, typically have enclosed cabs with large window assemblies to provide ventilation and to allow an operator a good view of their work environment. Frequently, these window assemblies provide multiple fixed and/or movable window panes within a perimeter frame.
In the art, during vehicle assembly, a window assembly can be attached to a body side wall as a single complete unit or in pieces. In most instances the window assembly is permanently attached from the outside of the vehicle by its perimeter frame with a weatherproof seal using compressible sealing rings, adhesives, and the like. Protective caging can also be added to the outside surface of the window assembly to protect window panes and the vehicle operator from stray impact.
Often these types of window assemblies have at least one slidable panel, such as a slidable window pane. Given the sometimes extreme work environment to which these window assemblies are exposed, it is desirable to secure the window pane from unintended travel along its path. Therefore, latch mechanisms associated with the slidable aspect of a window pane should provide a simple and rugged design to not only facilitate ease of movement of the window pane, but also to provide a means to secure the window in place at a plurality of positions along its travel path.
Known in the art are latching mechanisms for slidable windows that attach to a window pane corner or corners. For example, the latching mechanism can restrict window pane movement through the use of a locking pin on the latching mechanism that can selectively engage any one of a plurality of locking pin openings within a window assembly frame along its travel path. In one embodiment, the latching mechanism can be disengaged by squeezing two lever elements together to withdraw the locking pin from the window assembly frame. Other embodiments can provide two corner latching mechanisms that can require a user to simultaneously slide spring loaded locking pins out of the window frame. These types of mechanisms are common on windows with vertical travel paths.
Unfortunately, latching mechanisms positioned on a window pane corner can be difficult to operate (such as when a user is wearing gloves). Also, the window may bind during attempted travel. For example, this racking condition can occur when a user grabs the latching mechanism to unlatch the locking pin and push or pull the window to a new position. Specifically, the reactive moment causes a rotational value instead of a straight line pull. Overcoming the rotational effects of a corner pull may require an operator to use both hands to complete window movement. The same is true for dual latching mechanism on two corners of the same window pane.
Attempts to overcome the shortcomings of the rotational effect to a window as it travels along its path can provide a simple latching mechanism on or about the center of a window pane edge perpendicular to its travel path (e.g., along a vertical axis of a horizontally sliding window pane). See generally, U.S. Pat. No. 7,036,851 to Romig and EP 1 700 979 B1 to Jurgen et al. These solutions are not complete though in that it typically only retains movement of the window pane in its closed position and/or provides a complicated mechanism which may be a maintenance issue for window assemblies in harsh working environments. Thus, despite the advances of the current state of the art, further improvements in window latch mechanisms for slidable windows are possible and desired.